Aggressive children are at risk for later social, emotional, and behavioral problems. Children who start early a developmental trajectory of aggressive behavior are at particular risk for later maladjustment. Psychosocial interventions designed specifically for these early starters are generally supported by the empirical literature. Still, even with these interventions, a substantial portion of children do not respond to treatment or treatment gains are reduced at follow-up assessment. The goal of this study is to evaluate a selective prevention program for aggressive children in the elementary school grades that could potentially augment other, empirically based interventions. The Lunch Buddy sponsoring program is a simple yet innovative intervention strategy that involves regular lunchtime visits from a college student mentor. Created originally as a control condition, Lunch Buddy sponsoring was found to have unexpected benefits for aggressive, school age children in an earlier randomized controlled trial (RCT). Conceptually, this school-based sponsoring program is thought to enhance children's interactions with peers and alter peer-mediated contingencies that maintain aggressive behavior. Proposed is a small-scale RCT that will test, a priori, the hypothesis that Lunch Buddy sponsoring will lead to significant benefits for aggressive elementary school children. Participants (N = 60) will come from 15 elementary schools located in the mid-west. In late spring of Year 1, teachers will nominate children in grades 1, 2, and 3 who meet a behavioral description of an aggressive child. Recruited into the study are children who meet the following criteria: (a) a T score of 60 or above on the Aggressive Behavior subscale of the Teacher Report Form of the Child Behavior Checklist (Achenbach, 1991) and (b) a T score of 60 or above on the Aggressive Behavior subscale of the Parent Report Form of the Child Behavioral Checklist (Achenbach, 1991). Children will be randomly assigned to Lunch Buddy sponsoring or to a waitlist control condition. Mentoring will occur during the fall and spring semester of Year 2. Data from children, peers, teachers, and parents will be gathered pre- and post-intervention as well as at 1-year follow-up. Mentor-report data will be obtained during sponsoring and at post-treatment. Measured outcomes will include child aggression, lunchtime peer acceptance, social competence, school disciplinary actions, school connectedness, school attendance, and academic achievement. Analyses will examine the benefits of Lunch Buddy sponsoring for aggressive children. Also planned is the development of an observational coding scheme that will assess target children's lunchtime social interactions with nearby lunch mates. This observational measure will be piloted when children in the waitlist control condition are sponsored in Year 3. Findings from this study will provide a needed test of this promising intervention and its proposed mechanisms of change. Support for the efficacy of Lunch Buddy sponsoring would suggest that those responsible for the care and education of aggressive school-age children have an intervention option that complements more established but also more invasive intervention programs. PUBLIC HEALTH RELEVANCE: Children who begin displaying aggression and other conduct problems in early childhood are at risk for later antisocial behavior and delinquency. Perpetrators of violent and non-violent crimes impose a substantial cost to society. To the degree that Lunch Buddy mentoring is an efficacious way to help aggressive school age children, adults responsible for their care and education will have an intervention option that complements more established intervention programs and could substantially prevent the development of later conduct problems.